Bit Plane Browser and LSB Extraction

Bit Plane Browser and LSB Extraction Bit Plane Browser and LSB Extraction
2025-04-20 14:56:19 -04:00 · 2019-08-28 00:39:08 +01:00 · 2019-08-28 00:39:08 +01:00 · 4e8a79d8f1
commit 4e8a79d8f1
parent d3e3e6e6fc
3 changed files with 223 additions and 0 deletions
--- a/src/core/operations/ExtractLSB.mjs
+++ b/src/core/operations/ExtractLSB.mjs
@ -0,0 +1,114 @@
+/**
+ * @author Ge0rg3 [georgeomnet+cyberchef@gmail.com]
+ * @copyright Crown Copyright 2019
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation.mjs";
+import OperationError from "../errors/OperationError.mjs";
+import Utils from "../Utils";
+import { isImage } from "../lib/FileType";
+import jimp from "jimp";
+
+/**
+ * Extract LSB operation
+ */
+class ExtractLSB extends Operation {
+
+    /**
+     * ExtractLSB constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Extract LSB";
+        this.module = "Image";
+        this.description = "Extracts the Least Significant Bit data from each pixel in an image. This is a common way to hide data in Steganography.";
+        this.infoURL = "https://en.wikipedia.org/wiki/Bit_numbering#Least_significant_bit_in_digital_steganography";
+        this.inputType = "byteArray";
+        this.outputType = "byteArray";
+        this.args = [
+            {
+                name: "Colour Pattern #1",
+                type: "option",
+                value: COLOUR_OPTIONS,
+            },
+            {
+                name: "Colour Pattern #2",
+                type: "option",
+                value: ["", ...COLOUR_OPTIONS],
+            },
+            {
+                name: "Colour Pattern #3",
+                type: "option",
+                value: ["", ...COLOUR_OPTIONS],
+            },
+            {
+                name: "Colour Pattern #4",
+                type: "option",
+                value: ["", ...COLOUR_OPTIONS],
+            },
+            {
+                name: "Pixel Order",
+                type: "option",
+                value: ["Row", "Column"],
+            },
+            {
+                name: "Bit",
+                type: "number",
+                value: 0
+            }
+        ];
+    }
+
+    /**
+     * @param {File} input
+     * @param {Object[]} args
+     * @returns {File}
+     */
+    async run(input, args) {
+        if (!isImage(input)) throw new OperationError("Please enter a valid image file.");
+
+        const bit = 7 - args.pop(),
+            pixelOrder = args.pop(),
+            colours = args.filter(option => option !== "").map(option => COLOUR_OPTIONS.indexOf(option)),
+            parsedImage = await jimp.read(Buffer.from(input)),
+            width = parsedImage.bitmap.width,
+            height = parsedImage.bitmap.height,
+            rgba = parsedImage.bitmap.data;
+
+        if (bit < 0 || bit > 7) {
+            throw new OperationError("Error: Bit argument must be between 0 and 7");
+        }
+
+        let i, combinedBinary = "";
+
+        if (pixelOrder === "Row") {
+            for (i = 0; i < rgba.length; i += 4) {
+                for (const colour of colours) {
+                    combinedBinary += Utils.bin(rgba[i + colour])[bit];
+                }
+            }
+        } else {
+            let rowWidth;
+            const pixelWidth = width * 4;
+            for (let col = 0; col < width; col++) {
+                for (let row = 0; row < height; row++) {
+                    rowWidth = row * pixelWidth;
+                    for (const colour of colours) {
+                        i = rowWidth + (col + colour * 4);
+                        combinedBinary += Utils.bin(rgba[i])[bit];
+                    }
+                }
+            }
+        }
+
+        return Utils.convertToByteArray(combinedBinary, "binary");
+
+    }
+
+}
+
+const COLOUR_OPTIONS = ["R", "G", "B", "A"];
+
+export default ExtractLSB;